Some circuit arrangements are compact modules for power-electronic installations, in which different power components are connected up to form standardized subunits. In this case, parallel circuits of two or more transistors or diodes are produced in order to increase the maximum current-carrying capacity of the circuit.
FIG. 1 illustrates an example of a power module for switching large currents according to the prior art, and the electrical equivalent circuit diagram is shown in FIG. 2. Such an arrangement is disclosed for example in EP 0 427 143 B1 or EP 0 277 546 A1. In the case of the circuit illustrated, two semiconductor switching elements, in particular power IGBT, are present, which are in each case integrated in a semiconductor body 120, 122 and arranged on a carrying plate 160. The carrying plate 160 is usually constructed in two layers with a carrier 160b and a rear side metallization 160a. 
A top side, or at least part of the surface of the semiconductor bodies 120, 122 forms terminals 121, 123—in the present case the emitter or source terminals E—of the components. The gate terminals G are not illustrated separately in FIG. 1; they may be situated in a region of the surfaces which is insulated from the emitter or source terminals. The collector or drain terminals of the transistors integrated in the semiconductor bodies 120, 122 are usually formed by rear sides of the semiconductor bodies, which, in the case illustrated, are conductively connected to one another by a busbar 110 to which the semiconductor bodies are applied.
The terminals 121, 123 are connected by means of bonding wires 140, 142, of which a plurality are provided per device in order to increase the current-carrying capacity, to a common line, in the present case a busbar 130, which can be connected to a circuit potential.
The carrying plate 160 with the busbars 110, 130 may be designed as DCB substrate (DCB=direct copper bonding). The busbars 110, 130 are copper regions or copper islands on a ceramic substrate as carrier 40a. The rear side metallization is likewise composed of copper.
When the parallel-connected emitter-collector paths or drain-source paths (in series with a load) are connected to a supply voltage, high-frequency oscillations which lead to electromagnetic interference emissions arise both when the transistors are switched on, that is to say driven into the on state, and when the transistors are switched off, that is to say driven into the off state. Such oscillations are reported, for example, in Y. Takahashi, K. Yoshikawa, T. Koga, M. Soutome, T. Takano, H. Kirihata, Y. Seki: “Ultra high power 2.5 kV–1800 A Power Pack IGBT, Proceedings of ISPSD, 1997, 233–236 or B. Gutsmann, P. Mourick, D. Silber: “Explanation of IGBT Tail Current Oscillations by a Novel ‘Plasma Extraction Transit Time’ Mechanism”, 31st European Solid-State Device Research Conference ESSDERC, Sep. 11–13, 2001, 255–258.